Topic: Terry's NEW Redneck CB750 rebuild. The "Swamp Rat". Too soon? Nah..........

[Terry in Australia]

Ha ha, well in the old cemetery in my home town are several very old graves of Chinese miners who were eaten by Aborigines in the 1800's Per, the Aboriginals called Chinese Miners "Long Pig", apparently........... I must admit, I enjoy a good Chinese meal now and then, so I can understand why our Aboriginals did too!

Anyhoo, back to the swamp rat. Per asked what the wheel rims were like, and the answer is, not good. I don't think this will polish out.....

Terry's Swamp Rat CB750 rear wheel 1 May 2019 1 by Terry Prendergast, on Flickr

No biggie, I found a better one on Ebay in Queensland, it'lll be here in a couple of days, and I've got some expensive new "Stinko 712" tyres coming, when only the cheapest will do......

I pulled the spark plugs from #4 (points side) to #1, #4,3 and 2 looked good, but #1 was a problem. Ooops.

Terry's swamp rat spark plugs 28 Apr 2019 1 by Terry Prendergast, on Flickr

I put my bore scope camera thingy down the #1 spark plug hole, and it looked a bit like an American Christmas card, lots of white stuff on the piston. Bugger. I poured lots of ATF/Acetone mix down each spark plug hole, and cleaned the plugs and put them back in. Not confident.......

Terry's swamp rat spark plugs 28 Apr 2019 2 by Terry Prendergast, on Flickr

Good thing was the spark plug threads were nice and clean, with no cross-threading. That's a good thing.

[Terry in Australia]

That was actually yesterday. Today I remembered that I'd made my own "Frame Kit" many moons ago using old CB750 fork legs that were too far gone for forks, but perfect for temporarily joining the top frame rails, as the ID of the fork tubes is just about exactly the OD of the frame rails. How fcuking smart am I, fer a smelly ol' redneck?

First of all, I cut the section out, so I can take a peek under the cam cover tomorrow, to see if: 1, the cam and rockers are good, and 2, to see if it's got a nice hot cam lurking under that cam cover. Also, if I can't get the engine to turn over, I can remove the top end, in the frame. Sweet.

Look Ma, tons of room with no pesky frame rails to get in the way!

Terry's frame kit install 1 May 2019 1 by Terry Prendergast, on Flickr

So I did some a-drilling and a-bolting, and ended up with what I think is the strongest, best looking, most rigid frame kit that money can't buy, and unlike all those other woosey boy frame kits, it uses (some modified) genuine Honda parts! Sorry about the poor quality pics, but it was getting dark by the time I'd drilled 20 holes and bolted up 20 bolts with nyloc nuts. It looks filthy of course, but will look better once I sort the engine, paint the frame, and put it all back together again. Hoo Boy!;D

Terry's frame kit install 1 May 2019 2 by Terry Prendergast, on Flickr

Terry's frame kit install 1 May 2019 3 by Terry Prendergast, on Flickr

[MoMo]

Nice thrifty installation Terry....Larry

[PeWe]

That frame kit look very stable and stock Honda too!

The bad plug might have some corrosion only due to open valves letting extra moist in that cylinder. I guess that valve seats need a fresh cut. Hopefully no salty moist.

So Strynboen was right about the native cannibals  eating Chinese mine pigs!

That rim must have been in salt water for a while...

Or if the lost biker smoked some heavy stuff like fat black moldy Afghan with strange small white dots inside flying off the road right into the swamp or just rode into a pig trap... Locals thanked their star gods for the fat juicy pig making up a  pig roast for the local village. Years later they remembered the bike still out in the swamp....

Suddenly I see something good in cultures not eating pig.

[Terry in Australia]

Thanks guys, well it rained today, so no fun out in my driveway working on the Swamp Rat. I was hoping to whip off the cam cover and see what treasure lies within, but instead I had to stay inside and bake a loaf of fruit and nut bread. Yes I know, baking loaves of delicious fruit and nut bread isn't as exciting as working on corroded old rat bikes, but, well, I do so like home baked fruit and nut bread?

I did the "Buy it now" for a new pair of Stinko 712 tyres, plus tubes and rim bands, so at least that's covered, although I'm not entirely excited about fitting the tyres myself, still, new tyres are way easier to install than old hard tyres, so no biggie. The tyres will be here tomorrow, so I can strip/fit the front one on another front wheel I found in my garage that doesn't look to be in too bad condition, but the rear will have to wait until my new (to me) back wheel arrives from Queensland, probably on Monday or Tuesday. Once I've got tyres on serviceable wheels I can probably roll it off my trailer!

https://www.revzilla.com/common-tread/shinko-712-tire-review

Per mentioned that it has a later model head and he's quite right, in fact it's a much later engine, a 1975 model, but that's OK, only North America and Japan had a new K model every year, the rest of the world had K0-K2, then K6, so mine is still a K2, even though the engine and frame were built 3 years apart. Obviously "collector value" doesn't come into the equation with this bike as I've already cut the frame and lowered the collector value when I installed my frame kit yesterday, but I just want to build another good daily rider out of this piece of junk, so it's "value" will be based entirely on how much damn fun I'm having building, then riding it.     

Anyway, that's it, tomorrow is Friday, so hopefully the weather will be kinder to me and I can dig a bit deeper into the engine. Good news is it puked somee oil out of one of the oil hose ports and it was a nice greasy black color, and not a milky tan, which makes me think that the crankcases don't have any water in them, from sitting so long. Once I take that set of headers off (1 mangled phillips screw holding the bottom flange of header #2) Ill take a peek into the ports to see if a nice used 4 into 1 I've got hanging in my garage will fit. You never know your luck in a big city..........

[PeWe]

Same as my K2 1975. It should have the later head too.  We got K2 to 1975 until K6 came 1976
I have a really good refurbished one with ex seals. I have today no reason to open the valve cover nor head since it work fine with no leaks.

Lets see how that engine look like inside

[Terry in Australia]

Thanks Per, I'm hoping it's good, but the good thing is I have that 1975 F engine that I ran in my K2 "Bitsa" for a little while that is a beautiful engine, but the cases have been welded (badly) so I have everything I need to make it a good runner.

I have a new set of carb insulators for a K7 in a box somewhere, so I'm thinking of installing some spare F2 carbs on it, I ran them on another K bike years ago, and it ran way better than with the stock carbs, especially with the accelerator pump, I've even got an airbox for them, I think? Ah, playing with old swamp rats is so much more fun than expensive restos!  

[PeWe]

Expensive resto might not been the idea from the very beginning...reading posts here will give inspiration for hundreds of ways to drain the wallet.
And get admiring people hanging around the bike when parked talking about their old memories from the 70's

Lest follow your build Terry! You projects are usually very fun to follow (and comment) !!

[Terry in Australia]

Thanks Per!  Did I mention the engine is seized? I probably did, so over the last couple of days I've been working on it. I know some of you guys have fitted "frame kits", but I was always against cutting into a frame, and welding in lugs and all the other crappy "engineering" ideas folks were coming up with so they could take the top end off their engines without pulling the engine. When I was bored one weekend, I made my own kit, using buggared CB750 fork tubes for "sleeves", as they're a nice tight fit over the top support rails, so I cut four sections, drilled them for 6mm stainless bolts, slitted them for some extra clamping power, and last night, installed them on my "Swamp Rat" K2.

Friday K2 fiddling 3 May 2019 by Terry Prendergast, on Flickr

My new Stinko 712 tyres arrived today, so on the weekend I'll fit the front one, and hopefully the rear on Monday or Tuesday when my new (to me) rear wheel arrives from Queensland. I've done a little research on Stinko's, they're cheap, but yet Japanese quality, in fact, they're the old Yokohama tyres re-branded, and Yoko's weren't bad rubber, back in the day. The whitewall ones I had on my big black 'Wang, were actually pretty good. I might even put some on my Mad Max bike, when I get around to it.

Friday K2 fiddling 3 May 2019 2 by Terry Prendergast, on Flickr

But back to the bike.  I'd made a 50/50 mix of Acetone and ATF and tipped it into each cylinder via the spark plug holes last Monday night, but had no joy trying to get those pistons to move in their bores, so it was time for a little surgery. Whoever said that fitting a "frame kit" was butchery is full of sh1t, it's a great idea, who was that d1ckhead? Oh wait, it was me............. ooooops.

Friday K2 fiddling 3 May 2019 4 by Terry Prendergast, on Flickr

Under the valve cover, everything was surprisingly clean, the cam and cam towers are like new! The cam is a little mysterious, I'm not sure it's an OEM job.

Friday K2 fiddling 3 May 2019 7 by Terry Prendergast, on Flickr

Friday K2 fiddling 3 May 2019 5 by Terry Prendergast, on Flickr

Time to whip off the head. "Off with his head!"  Each cylinder was still full of ATF/Acetone mix. Either an excellent ring seal, or the rings are rusted completely to the cylinder walls....... oops.

Friday K2 fiddling 3 May 2019 9a by Terry Prendergast, on Flickr

Two cylinders were fine (closed valves) and 2 (with open valves) not so good......

Friday K2 fiddling 3 May 2019 9d by Terry Prendergast, on Flickr

No biggie, apart from having a good running spare engine, I've got lots of sleeves, pistons, big bore kits, blah blah blah, so once I unstick the 2 bad pistons, I'll get it sorted. I've got my own Repco Boring Bar so I can bore some cylinders if need be. I think the rest of the engine is actually pretty good, looking at the top end. Sweet............

Terry and Leo 28 Apr 2019 1 by Terry Prendergast, on Flickr

[spotty]

And get admiring people hanging around the bike when parked talking about their old memories from the 70's

I went to a 1%er's show with some mates years ago , they all had HD's, triumphs etc and I had my old honda4, matt black, orange pipes , calfskin seat, sissy bar, Maltese Cross mirrors and tail light, totally unbaffled pipes that didn't even make it all the way past the engine.. pure 70s
Unknowingly I followed everyone else into what I thought was the general parking area...nope, it was the show. The only jap bike in amongst a couple of hundred 1%er bikes, bit awkward so I just parked and walked away but kept an eye on it.it got way more attention than any of the chrome chariots around it and all positive.
As soon as all the big tuff bikers saw it they'd all start reminiscing about their old honda4's and kwaka9's and taking the piss out of each other for long forgotten exploits
And when I started it to ride out ...turned out to be louder than any of their toys

[PeWe]

These bikes are real time machines remember the old days !

Terry, Leo look forward to another project adding som fun to the thread, right?

Maybe the cylinder need some heat to let the pistons go? Heat gun on the sides all around for an hour or two. Watch out fot the boiling ATF acetone mix... Acetone boil very early, std aussy summer temperature like 40+C

[PeWe]

cam is intresting if diffetent than any CB750 cams. Measure.?
Head combustion chambers corroded too? Small holes/ dents...

[Terry in Australia]

Thanks men, Mark (Spotty) is spot on about old farts reminiscing about the good old days when our old rockets were still pretty new, just like we were. As much as shiny show bikes are nice to look at, restoring a bike to "better than new" wipes away it's history, and in a lot of cases the owners are more interested in putting them on trailers and towing them to shows than actually riding them.

Show bikes that aren't ridden are nothing more than statues in my opinion, so not for me. I'm not insulting anyone here, Per built a beautiful K2 out of nothing and he loves to ride it, so to me that's what building a bike is all about, turning someone else's junk into a living, breathing thing, that you actually ride and enjoy.

Talking about the cam, I took a peek at the other cams in my garage and became more and more confused, as they are all slightly different? I've got an early K0 cam that has virtually no base circle so I initially thought it was from a 500/4 until an expert pointed it out to me that I have a rare piece of Honda "unobtainium", then I found another one that is almost the same profile, but a different casting. Then there were 3 or 4 later cams with a much bigger base circle, so I need to measure the "lift" less the base circle diameter to find out which one had the most actual lift? I remember Hondaman saying that the K0 had the hottest cam (apart from the F2) bt I need that for my 1969 K0 engine build, so I'll probably just stick with the one that came out yesterday, as it looks like it's new.

Of course, if I decide to hot the engine up with a big bore kit, home-made port job etc, I might give that Megacycle 125/75 cam another go, unless someone here has a nice mild street cam they'd like to swap? OK, gotta get ready for a ride with Tim and his Royal Enfield, so better get dressed in all my motorcycle finery. Back later!

Terry and Leo 28 Apr 2019 by Terry Prendergast, on Flickr

[PeWe]

How big Big Bore kit?
My K6 runs fine with a RC295 profile cam, my new favorite. Much better from low and all over the rpm scale than DP315 and Megacycle 125-20. I compared all 3 cams in less than one week thanks to Franks frame kit. Both those cams are most likely designed for higher compression like 12.5-1 or more.
I tested the DP315 with different valve lash. Worked best with recommended lash of 0.3mm. Double or almost tripple other cams. The compression sank a lot with 0.10/0.15mm lash, power too due to the increased overlap making the doors to and from combustion chambers wide open too long.

That cam was a mystery cam found on eBay with no markings until I found RC295 lightly scratched on its side under the washer. I had to see from side to see it. Like the bearing markings on a crank. I measured it when timing and it matched the RC295 data.

Cam that give good power between 3000-6000 rpm is very useful on a street bike.
You have a frame kit so give that famous 125/75 grind a chance. Especially if you have 71mm bores or so. You might have an old good RC/DP295 cam somewhere?

[PeWe]

Les is still watching you when working with the bike? He is a bigger monster now than before....

[PeWe]

About very good restores, better and more shiny than new. I understand those that use it as a museum piece, not riding it making it dirty.
I had the same feeling with some NOS parts I have. NOS fenders that my K2 build got, they were ment for my K6 some day. Same with my NOS Honda K6 seat. I opened the box sometimes and looked at it until last spring some guys wrote that the seat on the bike is not matching the bike. So I did a 30 minute swap, started to use the expensive seat, price had even increased from $495 to $795 something plus shipping and customs.

My K6 has a set of NOS gauges in their boxes. Too good to be used.
My K2 build have old gauges I bought new faces I painted the rear sides looking like stock, upper black covers, glass and seals too. Closing the rings another obstacle. I could not quickly make a good tool doing it good without scratching, denting them so I gave up. Went from the garage into the kitchen. Ate something with 2 glasses of red wine while I thought about the NOS K2 gauges I have seen on eBay. Red wine is sometimes a great helper when deciding. I came to the conclusion that both I and the bike were well worth those gauges. Time is money too.
Speedo with km/h scale from Venezuela, Tacho from USA. Both their harnesses with rubber bulb holders had dried up completely so I was happy that I have new from Yamiya. The Venezuela guy filled in the shipping document correctly so the customs + VAT cost almost nothing. Good seller. I wonder how it works down there now after their internal chaos...?

I'll do the other gauges some day when I can crimp those rings easy and good looking as stock. I might sell them and get some back.

[Terry in Australia]

Good idea Per, I should sell lots of stuff in my garage, but I like looking at it, and occasionally I find something I need. Good example was today. I took your advice and heated the stuck piston with my gas torch before I sprayed some degreaser into each cylinder then gave the stuck piston a whacking with an alloy drift. Only took a couple of whacks, and it freed right up. Sweet. But I'm getting ahead of myself.

Firstly, I woke up nice and early for a saturday (0800) and made a big cup of coffee with my Aldi coffee machine, and an egg, bacon and cheese muffin. Yummo!

Terry's brekky 4 May 2019 by Terry Prendergast, on Flickr

Now today was Tim's first ride on his new Royal Enfield, but sadly it didn't last long, he had a low speed drop only a couple of miles from home, so we turned back for home. Not his fault, wet road, greasy new tyres, but no real damage apart from a bent clutch lever and dented pride. Oh well, I took the Harley for a longer run, then came back to start work on the swamp rat.

Terry and Tim ride Sat 4 May 2019 by Terry Prendergast, on Flickr

Of course, the weather didn't want to play the game:

Saturday Swamp Rat works 4 May 2019 by Terry Prendergast, on Flickr

But a little while later the sun came back out long enough to free the cylinder block from the bottom end.

Saturday Swamp Rat works 4 May 2019 1 by Terry Prendergast, on Flickr

Surprisingly the pistons weren't too bad, in the two good cylinders they were pretty much unmarked, the rings weren't stuck, no scratches etc. Even the two in the rusty bores were probably still useable, albeit with new rings.

Saturday Swamp Rat works 4 May 2019 2 by Terry Prendergast, on Flickr

Sadly the two cylinder sleeves were no good, my best honing efforts couldn't entirely remove the corrosion.

Swamprat rusted bores by Terry Prendergast, on Flickr

Swamprat rusted bores4 by Terry Prendergast, on Flickr

I went thru my collection of pistons and found 2 really good ones that Mike Beltrami sent me many years ago when he was a member here, so then went looking for some sleeves. I had lots of early sleeves without the two little notches in the top for the big rubber grommets that were used in the later cylinder block, but only found one decent later model sleeve. They say that necessity is the mother of invention, so I measured up an early sleeve, and modified a good one accordingly.

Saturday Swamp Rat works 4 May 2019 9a by Terry Prendergast, on Flickr

Saturday Swamp Rat works 4 May 2019 9c by Terry Prendergast, on Flickr

I'd put the cylinder block in my industrial oven and cooked the crap out of it, until the sleeves fell out of their own accord, then replaced the crappy sleeves with my "Reconditioned/repurposed" sleeves, that fitted like a finger in a bum.

Swamprat replacement sleeves 1 by Terry Prendergast, on Flickr

Hopefully tomorrow the weather will be kind to me, so I can re-assemble the top end. With luck I might even get to fire it up!



 

[BomberMann650]

Someone mentioned pastries?!


Don't fall for that stupid rhetoric PeWe.  It's all a lie.  The people who mind don't matter, and those who matter don't mind.

Go outside, ride a bike.

[PeWe]

Terry uou have really good tool and comptence using them too!

Sure the bottom end is OK?
Bad chains and tensioner.

You can inspect via oil pan, remove it to see and measure slack. Pump strainer might be clogged up with dirt, frogs, rat eggs and other things from the swamp.

[PeWe]

Good luck with the bike drop, not much damage.
 I think all of us have done same mistake in the beginning. I dropped my K6 some the first year. Learned about wet asphalt, white lines, tar repairs and metal stuff in the road that are very slippery when wet. Roads near gas stations, trucks leak diesel where road is curved.

[Terry in Australia]

Wow, I don't know what Cow-Man is smoking, but I want some too! Ha ha, thanks Per, The bottom end is still full of nice gooey black oil and I can feel that there's no slop in the big end bearings, so I'm confident that apart from the possibility of a chipped gear or worn dog, it'll probably be fine.

I will drop the sump pan and give the pump a good flush before I fire it up. There's a big dent in the clutch cover which I have to take off to remove the remains of the clutch cable and of course I'll be throwing the points ignition away in favour of an electronic ignition, and replacing that ugly arse points cover. OK, I better get outside and get into it!    

[PeWe]

What's the point running without points?
Hmmmm, that point cover reminds me about my blue K6 with a very cool(ing) cover

I'm sure you'll have a spare preadjusted point plate under the seat for future use, when bike has stopped somewhere!

[Terry in Australia]

Ha ha, I stopped carrying a spare points plate about 30 years ago Per, the only time I needed it was when one of my mate Peter's point arms broke in half. Nowadays you can't buy good points anyway, so get rid of that junk and add some cheap performance that you can set and forget.

Speaking of junk, I did more work on the swamp rat today. I found 2 really nice pistons that were a nice fit in the sleeves I installed yesterday, along with a couple of good wrist pins and circlips.

Sunday Swamp Rat fixing 5 May 2019 by Terry Prendergast, on Flickr

I gave the cylinder block a bit of a clean so that nothing would fall into the bottom end while I was installing the pistons, and with a lot of jiggling and farting about, I got the block back on. Sweet.

Sunday Swamp Rat fixing 5 May 2019 6 by Terry Prendergast, on Flickr

I celebrated with my current favourite drop, Stones "Ginger Joe". Twice as strong as beer, in a pint bottle. Life is good.......

Sunday Swamp Rat fixing 5 May 2019 2 by Terry Prendergast, on Flickr

It took a lot longer than I thought. I was hoping to get the head back on, but it was disgusting, so I spent an hour or so with a soft copper brush and a can of degreaser, then hit it with my garden hose to flush all the crap, dead spiders, leaves and greasy mud out of it, blew it dry with my air gun, then shoved it in my oven @ 100 deg C for 30 minutes or so to dry it properly. All going well, the sun will be shining tomorrow after work for an hour or so and I'll get the head back on.

Sunday Swamp Rat fixing 5 May 2019 5 by Terry Prendergast, on Flickr

I covered it up with my jacket and a towel and then put my new $16 bike cover over the whole dealio, as it looks like more rain overnight. Such is life when your "workshop" is a bike trailer in your driveway.

Sunday Swamp Rat fixing 5 May 2019  8 by Terry Prendergast, on Flickr

[PeWe]

You go forward very quick, Terry.

Headgasket? Std fiber from a gasket kit?
I installed cheap head gasket dry with the gasket kit on my K2. I re-tourqed it until nut not moved any further. It took me 3 days extra. Tightened again the day after the first...next day again and the day after. Finally not moving any further.  MLS does not need that many times. I should have known this procedure in the 80's, had saved me dirty engine weeping some. Common sense...

Have you found all bad threads? Valve cover, chain tensioner housing and any of the other covers must have 1 or 5 bad threads...

[Terry in Australia]

Thanks Per, I've got a box full of new head gaskets, maybe 20 or so? Genuine Honda (in the yellow packaging) plus aftermarket too? Whenever I built an 836cc engine I'd have to buy a complete gasket set, plus an 836cc head gasket, so just put the unused stock head gasket in the box.

I torque the head to 20 foot pounds in 4 pound feet increments from an initial 8 foot pounds, then leave it overnight, then back all the nuts off and do it all again, and apart from once when fhe head on a customers bike was warped, I've never had a head gasket leak.

I was going through my boxes of parts yesterday and also found a new main wiring harness, which was a bonus! I need new left and right switch blocks for the handlebars, but I won't order any until I've checked my other boxes, I've got a lot of crap left over from the Redneck "Bitsa" build that I haven't thoroughly explored.